Zarya is not a super model, no, but she's youthful and has a conventionally pretty face. The men are definitely in shape, as you say, but there's a much greater variety in appearance with them than with the female characters. Let's compare.
Characters who:
are fat: male 1, female 0/1 depending on what you think of Mei's body type. She certainly isn't fat in the way Roadhog is.
are visibly aged: male 5, female 0
have their face covered by default: male 5, female 0
are nonhuman: male 2, female 0, +Bastion
And then there's also the issue of physical disabilities. Junkrat and Torbjorn have visually obvious prosthetic limbs, while none of the women do (it's unclear whether other characters like Symmetra or McCree have prosthetics or just armor). Reaper and Genji's bodies have been completely destroyed and rebuilt, while on the women's side you have Mercy and Widowmaker. To be fair, Reaper and Genji's rebuilt bodies resemble conventionally attractive, fit bodies, but their faces are covered. Mercy looks 100% like a healthy, fit, attractive person, and Widow looks the same, but blue.
Basically, the male characters are allowed to have a much greater variation in character design that ventures outside the realm of conventionally sexy. That is not to say that nobody finds some of these more unconventional characters sexy; I mean, probably all of the characters including the nonhuman ones have someone out there who wants to bone them, but it's plainly obvious that the female characters conform much more closely to convention than the male ones do.
*deleted*
